Field of the Invention
The present invention relates to a method for multiplexing data and control sequences and mapping the multiplexed sequences to a physical channel in a wireless mobile communication system.
Discussion of the Related Art
Data and control sequences transmitted from a media access control (MAC) layer to a physical layer are encoded and then provide transport and control services through a radio transmission link. A channel coding scheme is comprised of a combination of processes of error detection, error correction, rate matching, interleaving, and mapping of transport channel information or control information to the physical channel. Data transmitted from the MAC layer includes systematic bits and non-systematic bits according to the channel coding scheme. The non-systematic bits may be parity bits.
In the 3rd generation partnership project (3GPP), an uplink shared channel (UL-SCH) and a random access channel (RACH) of an uplink transport channel may be mapped to a physical uplink shared channel (PUSCH) and a packet random access channel (PRACH) of a physical channel, respectively. Uplink control information (UCI), which is one from of uplink control channel information, may be mapped to a physical uplink control channel (PUCCH) and/or a PUSCH. In a channel such as a UL-SCH, processing for cyclic redundancy check (CRC), code block segmentation, channel coding, rate matching, and code block concatenation is performed with respect to at least one transport channel or control information.
A process for processing a transport channel and/or control information is illustrated in FIG. 1. Data in the form of a transport block is input every transmission time interval (TTI). The transport block is processed as follows. A CRC attachment block attaches a CRC to the data in the form of a transport block. A code block segmentation block segments the CRC-attached data into one or more code blocks. A channel coding block performs channel coding for a code block data stream of each of the segmented code blocks. A rate matching block performs rate matching for the channel coded data stream. A code block concatenation block concatenates one or more rate-matched data streams to form a sequence of encoded data bits. Meanwhile, a separate channel coding block performs channel coding for control information to form a sequence of encoded control bits. A data/control multiplexing block multiplexes the sequence of encoded data bits and the sequence of encoded control bits, thereby generating a sequence of multiplexed bits.
One symbol may be comprised of at least one bit according to a modulation order (Qm). For example, for BPSK, QPSK, 16QAM, and 64QAM, one bit, two bits, four bits, and six bits corresponding respectively thereto constitute one symbol. In a system using single-carrier frequency division multiple access (SC-FDMA), one symbol is mapped to one resource element (RE), and therefore, a description can be given in units of symbols.
A conventional transport channel processing is illustrated in FIG. 2. FIG. 2 illustrates n resource blocks (RBs) having a matrix structure of ‘R’ rows by ‘C’ columns (R*C) (for example, C=14). C successive symbols are arranged in a time area in a horizontal direction and R subcarriers are arranged in a frequency area in a vertical direction. In a normal cyclic prefix (CP) configuration, 14 (C=14) symbols constitute one sub-frame. In an extended CP configuration, 12 (C=12) symbols may constitute one sub-frame. That is, FIG. 2 is based on the normal CP configuration. If the extended CP configuration is used, FIG. 2 may have a matrix structure in which C is 12. Referring to FIG. 2, M symbols (=the number of symbols×the number of subcarriers=C×R) may be mapped with respect to one RB. Namely, M symbols may be mapped to M resource elements per RB. In addition to symbols generated by multiplexing data symbols and control symbols, reference signal (RS) symbols and/or sounding RS (SRS) symbols may be mapped to the M resource elements. Therefore, if K RS symbols and/or SRS symbols are mapped, (M-K) multiplexed symbols may be mapped.
In FIG. 2, multiplexed data and control information are mapped to a data channel in units of modulation symbols in consideration of a modulation order. Mapping is performed rightwards starting from a left-top position of the first RB. If mapping is completed, mapping for the next subcarrier is performed. Within each subcarrier, mapping is implemented rightwards. Multiplexing may be carried out by inserting or rate-matching control information to a position at which the control information out of data information is to be mapped. Alternatively, multiplexing may be performed by puncturing data information. When multiplexed data and control information are mapped to a data channel, the control information is mapped to SC-FDMA symbols near to an RS which is less influenced by in high-speed mobile environment, and the data is mapped in a manner of avoiding SC-FDMA symbols allocated for control information and RS mapping, that is, the data is mapped to REs except for REs of positions of those SC-FDMA symbols.
According to the method of FIG. 2, when various types of control information are mapped, the locations of the respective control information can not be determined. In addition, if the amount of control information which can be included per SC-FDMA symbol is calculated in consideration of the length of the control information and a modulation order and then the control information is multiplexed with data, for example, if control information 1 is mapped to REs near to an RS and control information 2 is mapped to REs apart from the RS, unbalance occurs between the control information 1 and the control information 2. Accordingly, if a capability condition demanded by the control information 2 is higher than a capability condition demanded by the control information 1, the capability condition demanded by the control information 2 may not be satisfied. Moreover, if the control information 1 is rate-matched with the data for multiplexing and if the control information 2 punctures data for multiplexing, data of code blocks input first by the control information 2 can not be mapped to REs near to the RS relative to data of code blocks which is input later. Namely, the control information 2 may be mapped so as to be concentrate upon a specific RB. The nearer REs are to the RS, the better transmission performance is. However, if different error rates occur for respective code blocks in the same transmission environment, transmission system performance may be degraded,